Viruses of the family Baculoviridae, commonly known as baculoviruses, are lethal pathogens of insects of the order Lepidoptera. These viruses typically kill their hosts by productive, lytic infection in insect tissues.
Baculoviruses generally contain a covalently closed, circular double-stranded DNA genome of about 90 to 160 kb in length. This genome is capable of accommodating relatively long heterologous sequences. In addition, a high level of structural viral protein synthesis is achieved during productive infection. Consequently, the baculovirus/insect cell system has become a popular protein expression vehicle for academic research and industrial applications. However, since high level expression is coincident with productive infection and late gene expression, the baculovirus expression system is limited by the eventual death of the baculovirus-infected culture.